Pub Date : 2026-01-15DOI: 10.1016/j.optcom.2026.132910
Chon-Fai Kam
We investigate classical nonlinear optical analogues of excited-state quantum phase transitions (ESQPTs) within a squeezing-enhanced generalized Lipkin–Meshkov–Glick (LMG) model, focusing on polarization dynamics in optical fibers with tetragonal symmetry. Through systematic mapping of coupled-mode equations across crystal symmetries, we identify a novel non-conventional squeezing term that induces classical bifurcations—even without a linear rotor term. These bifurcations, analyzed in detail on the Poincaré sphere, correspond—via established semiclassical correspondence—to singularities in excited-state spectra characteristic of ESQPTs in the quantum LMG counterpart. Our findings highlight deep classical–quantum interplay in optical systems, providing a controllable room-temperature platform for simulating mean-field limits of many-body quantum criticality, with potential applications in quantum metrology and simulation. Full quantum spectral analysis is deferred to future work.
{"title":"Classical optical analogues of excited-state quantum phase transitions in a squeezing-enhanced generalized Lipkin–Meshkov–Glick model","authors":"Chon-Fai Kam","doi":"10.1016/j.optcom.2026.132910","DOIUrl":"10.1016/j.optcom.2026.132910","url":null,"abstract":"<div><div>We investigate classical nonlinear optical analogues of excited-state quantum phase transitions (ESQPTs) within a squeezing-enhanced generalized Lipkin–Meshkov–Glick (LMG) model, focusing on polarization dynamics in optical fibers with tetragonal symmetry. Through systematic mapping of coupled-mode equations across crystal symmetries, we identify a novel non-conventional squeezing term that induces classical bifurcations—even without a linear rotor term. These bifurcations, analyzed in detail on the Poincaré sphere, correspond—via established semiclassical correspondence—to singularities in excited-state spectra characteristic of ESQPTs in the quantum LMG counterpart. Our findings highlight deep classical–quantum interplay in optical systems, providing a controllable room-temperature platform for simulating mean-field limits of many-body quantum criticality, with potential applications in quantum metrology and simulation. Full quantum spectral analysis is deferred to future work.</div></div>","PeriodicalId":19586,"journal":{"name":"Optics Communications","volume":"606 ","pages":"Article 132910"},"PeriodicalIF":2.5,"publicationDate":"2026-01-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145981667","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Novel reflection and transparent optical elements containing replicas of rough surface areas were experimentally studied as an alternative to traditional security holograms. These elements provide a physically unclonable function while allowing for mass replication from a master stamp. The sensitivity of the replica identification process to positioning inaccuracies was determined, and methods for reducing this sensitivity were proposed and experimentally tested. This allowed for an increase in permissible lateral shifts by more than an order of magnitude. For transparent elements, the permissible tilt value increased by two orders of magnitude compared to reflection elements.
{"title":"Identification of rough surface replicas","authors":"A.M. Smolovich , A.P. Orlov , A.V. Frolov , L.D. Klebanov , I.D. Laktaev , P.A. Smolovich , O.V. Butov","doi":"10.1016/j.optcom.2026.132915","DOIUrl":"10.1016/j.optcom.2026.132915","url":null,"abstract":"<div><div>Novel reflection and transparent optical elements containing replicas of rough surface areas were experimentally studied as an alternative to traditional security holograms. These elements provide a physically unclonable function while allowing for mass replication from a master stamp. The sensitivity of the replica identification process to positioning inaccuracies was determined, and methods for reducing this sensitivity were proposed and experimentally tested. This allowed for an increase in permissible lateral shifts by more than an order of magnitude. For transparent elements, the permissible tilt value increased by two orders of magnitude compared to reflection elements.</div></div>","PeriodicalId":19586,"journal":{"name":"Optics Communications","volume":"606 ","pages":"Article 132915"},"PeriodicalIF":2.5,"publicationDate":"2026-01-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145981657","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2026-01-13DOI: 10.1016/j.optcom.2026.132893
Andrew MacRae , Connor Kupchak
We study the limitations on observing transient amplification in atomic systems exhibiting electromagnetically induced transparency (EIT) and we evaluate the limits of optical Bloch equation (OBE) models. Using propagation-based Maxwell–Bloch simulations, we show that single-atom, spatially uniform OBE treatments overestimate gain by neglecting propagation dynamics. In two-level systems, this yields incorrect predictions of the transmission, while in three-level systems, it predicts unrealistically large amplification. Furthermore, we show that Doppler averaging in warm vapor suppresses oscillatory ringing and the maximum achievable gain. Our results explain discrepancies between OBE predictions and experimental observations, and establish practical limits on transient gain in cold and thermally broadened EIT media.
{"title":"Propagation dynamics and transient amplification in warm and cold atomic EIT systems","authors":"Andrew MacRae , Connor Kupchak","doi":"10.1016/j.optcom.2026.132893","DOIUrl":"10.1016/j.optcom.2026.132893","url":null,"abstract":"<div><div>We study the limitations on observing transient amplification in atomic systems exhibiting electromagnetically induced transparency (EIT) and we evaluate the limits of optical Bloch equation (OBE) models. Using propagation-based Maxwell–Bloch simulations, we show that single-atom, spatially uniform OBE treatments overestimate gain by neglecting propagation dynamics. In two-level systems, this yields incorrect predictions of the transmission, while in three-level systems, it predicts unrealistically large amplification. Furthermore, we show that Doppler averaging in warm vapor suppresses oscillatory ringing and the maximum achievable gain. Our results explain discrepancies between OBE predictions and experimental observations, and establish practical limits on transient gain in cold and thermally broadened EIT media.</div></div>","PeriodicalId":19586,"journal":{"name":"Optics Communications","volume":"606 ","pages":"Article 132893"},"PeriodicalIF":2.5,"publicationDate":"2026-01-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145980884","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2026-01-13DOI: 10.1016/j.optcom.2026.132883
Jabir Hakami , Abu Mohamed Alhasan , A.Y. Madkhli , Salah Abdulrhmann
In this article, we present findings on the impacts of external optical feedback (OFB), non-radiative recombination (NRR), and injection current on the lasing field fluctuations and the spectral characteristics of laser diodes (LDs). Utilizing an advanced simulation model, we explore OFB as a series of round trip time delays in the external-cavity. Our research categorizes laser dynamics through bifurcation diagrams of photon numbers and analyzes noise characteristics across three operational regions: continuous-wave (CW) operation under weak OFB, chaotic behavior under moderate OFB, and stable CW operation under strong OFB. Notably, lower NRR stabilize laser output, facilitating periodic oscillation (PO) or CW modes essential for high performance. Reducing the NRR in solitary lasers narrows the line shape, enhancing optical performance. In CW operation under strong OFB conditions, low-frequency components of relative intensity noise (RIN) and frequency noise (FN) are substantially suppressed. However, noise levels increase during coherence collapse and at higher NRR. Our findings indicate that while moderate OFB can induce coherence collapse leading to broadened spectral peaks, very strong OFB enhances coherence, yielding sharp central peaks and allowing for CW or PO. Overall, our research highlights the critical role of a low NRR in enhancing the stability of laser diodes while revealing that a higher NRR can improve coherence in specific contexts. These insights pave the way for future advancements in laser technology, particularly for applications requiring precision and reliability.
{"title":"Impact of non-radiative recombination and optical feedback strength on field fluctuations, noise, and spectral line shape in laser diodes","authors":"Jabir Hakami , Abu Mohamed Alhasan , A.Y. Madkhli , Salah Abdulrhmann","doi":"10.1016/j.optcom.2026.132883","DOIUrl":"10.1016/j.optcom.2026.132883","url":null,"abstract":"<div><div>In this article, we present findings on the impacts of external optical feedback (OFB), non-radiative recombination (NRR), and injection current on the lasing field fluctuations and the spectral characteristics of laser diodes (LDs). Utilizing an advanced simulation model, we explore OFB as a series of round trip time delays in the external-cavity. Our research categorizes laser dynamics through bifurcation diagrams of photon numbers and analyzes noise characteristics across three operational regions: continuous-wave (CW) operation under weak OFB, chaotic behavior under moderate OFB, and stable CW operation under strong OFB. Notably, lower NRR stabilize laser output, facilitating periodic oscillation (PO) or CW modes essential for high performance. Reducing the NRR in solitary lasers narrows the line shape, enhancing optical performance. In CW operation under strong OFB conditions, low-frequency components of relative intensity noise (RIN) and frequency noise (FN) are substantially suppressed. However, noise levels increase during coherence collapse and at higher NRR. Our findings indicate that while moderate OFB can induce coherence collapse leading to broadened spectral peaks, very strong OFB enhances coherence, yielding sharp central peaks and allowing for CW or PO. Overall, our research highlights the critical role of a low NRR in enhancing the stability of laser diodes while revealing that a higher NRR can improve coherence in specific contexts. These insights pave the way for future advancements in laser technology, particularly for applications requiring precision and reliability.</div></div>","PeriodicalId":19586,"journal":{"name":"Optics Communications","volume":"606 ","pages":"Article 132883"},"PeriodicalIF":2.5,"publicationDate":"2026-01-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145980883","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2026-01-12DOI: 10.1016/j.optcom.2026.132908
Jie Zhao , Zizhuo Li , Zhenxing Sun , Yanqiu Xu , Jin Zhang , Kaifei Tang , Jiaqiang Nie , Rulei Xiao , Xiangfei Chen
In this work, we present a high-order colliding pulse mode-locked lasers (CPML) based on a 500 μm cavity length Fabry-Perot saturable absorber (FP-SA) unit operating in the C-band. The laser employs a high-power epitaxial structure and asymmetric reflectance coatings, featuring a 95 % high-reflective (HR) coating on one facet and a naturally cleaved facet on the other. This design enhances intracavity energy density, optimizes pulse compression, and achieves cavity-length extension and performance refinement through modular multi-stage cascading. We systematically investigate the mode-locking dynamics of the SA-FP unit and cascaded systems (second to fourth order), demonstrating stable generation of optical pulses with 88.2 GHz longitudinal mode spacing and robust stability against current and temperature variations. Furthermore, to enable high-speed transmission on individual comb lines, a four-channel DWDM experiment is conducted at the 4th-order CPML’s central wavelength. Utilizing a thin-film LiNbO3 Mach-Zehnder interferometer (MZI) modulator, each channel achieve 25 Gb/s non-return-to-zero (NRZ) modulation capability. The proposed high-order CPML architecture serves as a superior comb source for energy-efficient optical interconnects and high-bandwidth data transmission, offering a scalable platform for next-generation photonic systems.
{"title":"High-order colliding-pulse mode-locked lase with high power and mode stability for optical I/O technology","authors":"Jie Zhao , Zizhuo Li , Zhenxing Sun , Yanqiu Xu , Jin Zhang , Kaifei Tang , Jiaqiang Nie , Rulei Xiao , Xiangfei Chen","doi":"10.1016/j.optcom.2026.132908","DOIUrl":"10.1016/j.optcom.2026.132908","url":null,"abstract":"<div><div>In this work, we present a high-order colliding pulse mode-locked lasers (CPML) based on a 500 μm cavity length Fabry-Perot saturable absorber (FP-SA) unit operating in the C-band. The laser employs a high-power epitaxial structure and asymmetric reflectance coatings, featuring a 95 % high-reflective (HR) coating on one facet and a naturally cleaved facet on the other. This design enhances intracavity energy density, optimizes pulse compression, and achieves cavity-length extension and performance refinement through modular multi-stage cascading. We systematically investigate the mode-locking dynamics of the SA-FP unit and cascaded systems (second to fourth order), demonstrating stable generation of optical pulses with 88.2 GHz longitudinal mode spacing and robust stability against current and temperature variations. Furthermore, to enable high-speed transmission on individual comb lines, a four-channel DWDM experiment is conducted at the 4th-order CPML’s central wavelength. Utilizing a thin-film LiNbO<sub>3</sub> Mach-Zehnder interferometer (MZI) modulator, each channel achieve 25 Gb/s non-return-to-zero (NRZ) modulation capability. The proposed high-order CPML architecture serves as a superior comb source for energy-efficient optical interconnects and high-bandwidth data transmission, offering a scalable platform for next-generation photonic systems.</div></div>","PeriodicalId":19586,"journal":{"name":"Optics Communications","volume":"606 ","pages":"Article 132908"},"PeriodicalIF":2.5,"publicationDate":"2026-01-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145981668","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2026-01-12DOI: 10.1016/j.optcom.2026.132901
Peng Song, Le Li, Chengtao Liu, Lijian Zhang, Hua Guo
To address the intrinsic limitations imposed by the low received signal strength and the consequent restrictions on coverage range, in ultraviolet non-line-of-sight (UV NLOS) communication, this study establishes a three-dimensional spatial light-field distribution model for ultraviolet reflective channels. By integrating bidirectional reflectance distribution function (BRDF) theory with light reflection theory for rough surfaces, we calculate the reflectivity of ultraviolet light reflected from such surfaces and develop a three-stage physical model that characterizes the energy transfer of ultraviolet photons via a reflective surface to a sampling point. A Monte Carlo method is proposed to compute the three-dimensional spatial distribution of the ultraviolet reflection channel. Experimental verification employs a combined micro- and macro-scale approach. At the microscopic level, experiments confirm the accuracy of the BRDF model for cement surfaces within the solar-blind band under varying incident and reflection azimuth angles. At the macroscopic level, field experiments, supplemented by light-field simulations, reveal the effects of LED divergence angle and transmitter elevation angle on the energy distribution of the reflected light-field. The strong correlation between experimental and simulation results verifies the effectiveness of the proposed reflected light-field calculation method. This study provides a new approach for overcoming the distance bottleneck in UV NLOS communication and offers valuable insights for the design of covert communication systems in complex environments.
{"title":"Light-field distribution analysis in reflective ultraviolet communication channels","authors":"Peng Song, Le Li, Chengtao Liu, Lijian Zhang, Hua Guo","doi":"10.1016/j.optcom.2026.132901","DOIUrl":"10.1016/j.optcom.2026.132901","url":null,"abstract":"<div><div>To address the intrinsic limitations imposed by the low received signal strength and the consequent restrictions on coverage range, in ultraviolet non-line-of-sight (UV NLOS) communication, this study establishes a three-dimensional spatial light-field distribution model for ultraviolet reflective channels. By integrating bidirectional reflectance distribution function (BRDF) theory with light reflection theory for rough surfaces, we calculate the reflectivity of ultraviolet light reflected from such surfaces and develop a three-stage physical model that characterizes the energy transfer of ultraviolet photons via a reflective surface to a sampling point. A Monte Carlo method is proposed to compute the three-dimensional spatial distribution of the ultraviolet reflection channel. Experimental verification employs a combined micro- and macro-scale approach. At the microscopic level, experiments confirm the accuracy of the BRDF model for cement surfaces within the solar-blind band under varying incident and reflection azimuth angles. At the macroscopic level, field experiments, supplemented by light-field simulations, reveal the effects of LED divergence angle and transmitter elevation angle on the energy distribution of the reflected light-field. The strong correlation between experimental and simulation results verifies the effectiveness of the proposed reflected light-field calculation method. This study provides a new approach for overcoming the distance bottleneck in UV NLOS communication and offers valuable insights for the design of covert communication systems in complex environments.</div></div>","PeriodicalId":19586,"journal":{"name":"Optics Communications","volume":"606 ","pages":"Article 132901"},"PeriodicalIF":2.5,"publicationDate":"2026-01-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145981661","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2026-01-12DOI: 10.1016/j.optcom.2026.132875
Heyam Hassan , Saud Althunibat , Scott Miller , Mazen Hasna , Khalid Qaraqe
Hybrid Free-Space Optical (FSO)/millimeter wave (mmWave) communication systems have garnered significant attention due to their ability to deliver high data rates while maintaining reliable connectivity across diverse atmospheric conditions. However, traditional switching mechanisms, such as signal-to-noise ratio (SNR) threshold-based, rely only on the link’s instantaneous SNR, ignoring the link’s bandwidth, which degrades the overall system’s reliability and efficiency. In order to mitigate this challenge, a channel capacity-based switching scheme for a hybrid FSO/mmWave system is proposed in this paper. Unlike existing schemes, the proposed mechanism dynamically switches between FSO and mmWave links based on the estimated channel capacity of the two links, rather than relying only on instantaneous channel conditions. This ensures that the system always selects the link with the highest achievable capacity, thereby improving the system’s throughput. The analysis incorporates both intensity modulation/direct detection (IM/DD) and heterodyne detection (HD) techniques under various weather conditions, including clear, hazy, and rainy scenarios. The FSO channel is modeled using the Gamma–Gamma (GG) distribution, while the mmWave link follows the Nakagami-m fading model. Closed-form expressions for key performance metrics, including link utilization and channel capacity for FSO, RF, and the proposed hybrid scheme, are derived and validated through simulation. Additionally, a comparative analysis conducted against existing switching mechanisms demonstrates that the proposed approach significantly enhances the performance of the hybrid FSO/mmWave system.
{"title":"A new selection mechanism for hybrid FSO/mmWave systems","authors":"Heyam Hassan , Saud Althunibat , Scott Miller , Mazen Hasna , Khalid Qaraqe","doi":"10.1016/j.optcom.2026.132875","DOIUrl":"10.1016/j.optcom.2026.132875","url":null,"abstract":"<div><div>Hybrid Free-Space Optical (FSO)/millimeter wave (mmWave) communication systems have garnered significant attention due to their ability to deliver high data rates while maintaining reliable connectivity across diverse atmospheric conditions. However, traditional switching mechanisms, such as signal-to-noise ratio (SNR) threshold-based, rely only on the link’s instantaneous SNR, ignoring the link’s bandwidth, which degrades the overall system’s reliability and efficiency. In order to mitigate this challenge, a channel capacity-based switching scheme for a hybrid FSO/mmWave system is proposed in this paper. Unlike existing schemes, the proposed mechanism dynamically switches between FSO and mmWave links based on the estimated channel capacity of the two links, rather than relying only on instantaneous channel conditions. This ensures that the system always selects the link with the highest achievable capacity, thereby improving the system’s throughput. The analysis incorporates both intensity modulation/direct detection (IM/DD) and heterodyne detection (HD) techniques under various weather conditions, including clear, hazy, and rainy scenarios. The FSO channel is modeled using the Gamma–Gamma (GG) distribution, while the mmWave link follows the Nakagami-m fading model. Closed-form expressions for key performance metrics, including link utilization and channel capacity for FSO, RF, and the proposed hybrid scheme, are derived and validated through simulation. Additionally, a comparative analysis conducted against existing switching mechanisms demonstrates that the proposed approach significantly enhances the performance of the hybrid FSO/mmWave system.</div></div>","PeriodicalId":19586,"journal":{"name":"Optics Communications","volume":"606 ","pages":"Article 132875"},"PeriodicalIF":2.5,"publicationDate":"2026-01-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145981669","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2026-01-12DOI: 10.1016/j.optcom.2026.132906
Xuan Chen, Minghua Cao, Yue Zhang, Huiqin Wang
Optical filter-bank multicarrier with index modulation (OFBMC-IM) suffers from reduced spectral efficiency due to inactive subcarriers. To address this issue, we propose a dual-mode scheme for OFBMC-IM system (DM-OFBMC-IM), which assigns distinct constellation modes to all subcarriers, thereby achieving full carrier utilization while preserving the diversity gain of index modulation. To further enhance bit error rate (BER) performance, phase rotation and amplitude scaling are introduced to adjust both the angular and radial positions of constellation points, generating IM-preferable constellations. Additionally, a deep learning-aided detector, named DMOFIMNet, is developed to recover index and symbol information under channel turbulence, and its hyperparameters are optimized using the Artificial Lemming Algorithm (ALA), thereby maximizing the achievable performance. Simulation and experimental results demonstrate that the proposed DM-OFBMC-IM system not only achieves higher spectral efficiency than benchmark systems but also improves BER performance. In addition, compared to the classical maximum-likelihood detector, the proposed detector reduces computational complexity by approximately 25% while achieving near-optimal BER performance.
{"title":"Deep learning-aided dual-mode index modulation FBMC for optical wireless communications","authors":"Xuan Chen, Minghua Cao, Yue Zhang, Huiqin Wang","doi":"10.1016/j.optcom.2026.132906","DOIUrl":"10.1016/j.optcom.2026.132906","url":null,"abstract":"<div><div>Optical filter-bank multicarrier with index modulation (OFBMC-IM) suffers from reduced spectral efficiency due to inactive subcarriers. To address this issue, we propose a dual-mode scheme for OFBMC-IM system (DM-OFBMC-IM), which assigns distinct constellation modes to all subcarriers, thereby achieving full carrier utilization while preserving the diversity gain of index modulation. To further enhance bit error rate (BER) performance, phase rotation and amplitude scaling are introduced to adjust both the angular and radial positions of constellation points, generating IM-preferable constellations. Additionally, a deep learning-aided detector, named DMOFIMNet, is developed to recover index and symbol information under channel turbulence, and its hyperparameters are optimized using the Artificial Lemming Algorithm (ALA), thereby maximizing the achievable performance. Simulation and experimental results demonstrate that the proposed DM-OFBMC-IM system not only achieves higher spectral efficiency than benchmark systems but also improves BER performance. In addition, compared to the classical maximum-likelihood detector, the proposed detector reduces computational complexity by approximately 25% while achieving near-optimal BER performance.</div></div>","PeriodicalId":19586,"journal":{"name":"Optics Communications","volume":"606 ","pages":"Article 132906"},"PeriodicalIF":2.5,"publicationDate":"2026-01-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145981666","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2026-01-10DOI: 10.1016/j.optcom.2026.132876
Jingyao Hou , Xueping Sun , Chen He , Xizhi Wan , Wang Wang , Ziyu Tian , Shuyi Wang , Shun Zhou , Weiguo Liu , Jin Cheng , Siqi Wang , Jiaming Su
Smoke can scatter and absorb laser beams, leading to significant attenuation and reduced detection accuracy of detectors. In this study, we investigated the capacity of vortex beams with orbital angular momentum (OAM) to mitigate the scattering effects and explored the transmission behavior of Laguerre-Gaussian (LG) beams in smoke at various concentrations. Based on the physical characteristics of smoke particles, the particle size distribution was characterized, and smoke cluster particles were generated using the cluster-cluster aggregation (CCA) model. We examined the effects of the wind speed intensity on smoke diffusion and generate a non-uniform smoke environment. Subsequently, we conducted simulations and experiments to analyze and quantify the scattering and OAM crosstalk properties of LG vortex beams in a smoky environment. The results demonstrate that an increase in the topological charge of an LG vortex beam enhances its transmission capability and results in stronger scattering following interaction with smoke particles. Furthermore, the increase in smoke concentration exacerbates the distortion of the vortex light phase diagram, causing crosstalk from the initial topological value to extend into adjacent modes. At a smoke transmittance of 12.61 %, the original topology (l = 5) remains identifiable, which demonstrates that vortex beams exhibit relatively robust transmission properties under smoky conditions. These findings can serve as a technical reference for improving the resistance of laser systems to smoke interference and offer data support for real-time target reconstruction.
{"title":"Transmission characteristics of Laguerre–Gaussian vortex beams under scattering in a smoky environment","authors":"Jingyao Hou , Xueping Sun , Chen He , Xizhi Wan , Wang Wang , Ziyu Tian , Shuyi Wang , Shun Zhou , Weiguo Liu , Jin Cheng , Siqi Wang , Jiaming Su","doi":"10.1016/j.optcom.2026.132876","DOIUrl":"10.1016/j.optcom.2026.132876","url":null,"abstract":"<div><div>Smoke can scatter and absorb laser beams, leading to significant attenuation and reduced detection accuracy of detectors. In this study, we investigated the capacity of vortex beams with orbital angular momentum (OAM) to mitigate the scattering effects and explored the transmission behavior of Laguerre-Gaussian (LG) beams in smoke at various concentrations. Based on the physical characteristics of smoke particles, the particle size distribution was characterized, and smoke cluster particles were generated using the cluster-cluster aggregation (CCA) model. We examined the effects of the wind speed intensity on smoke diffusion and generate a non-uniform smoke environment. Subsequently, we conducted simulations and experiments to analyze and quantify the scattering and OAM crosstalk properties of LG vortex beams in a smoky environment. The results demonstrate that an increase in the topological charge of an LG vortex beam enhances its transmission capability and results in stronger scattering following interaction with smoke particles. Furthermore, the increase in smoke concentration exacerbates the distortion of the vortex light phase diagram, causing crosstalk from the initial topological value to extend into adjacent modes. At a smoke transmittance of 12.61 %, the original topology (<em>l</em> = 5) remains identifiable, which demonstrates that vortex beams exhibit relatively robust transmission properties under smoky conditions. These findings can serve as a technical reference for improving the resistance of laser systems to smoke interference and offer data support for real-time target reconstruction.</div></div>","PeriodicalId":19586,"journal":{"name":"Optics Communications","volume":"606 ","pages":"Article 132876"},"PeriodicalIF":2.5,"publicationDate":"2026-01-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145981660","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2026-01-10DOI: 10.1016/j.optcom.2026.132905
Rajib Lochan Ghadei, Rishi Maiti
Solar energy, the most abundant renewable resource on Earth, offers a clean and sustainable solution to meet the rising global energy demand. However, existing metamaterial-based solar absorbers often suffer from limited broadband absorption, polarization sensitivity, and narrow angular response, which restrict their practical applicability. To overcome these challenges, we propose a novel Ti/SiO2/Ti cross-ring metasurface absorber that synergistically exploits localized surface plasmon resonance, Fabry-Pérot cavity resonance, and magnetic resonance within a single subwavelength unit cell. This multi-resonant coupling enables broadband, polarization-insensitive, and wide-angle absorption performance. Using Lumerical FDTD simulations, the proposed absorber achieves an average absorption of 94.2 % across a wide spectral range of 280–5000 nm, with maximum average absorptions of 96.0 % and 95.8 % for transverse electric and transverse magnetic polarizations, respectively. Near-perfect absorption peaks of 99.9 % are observed at resonance wavelengths of 334 nm and 658 nm. Moreover, the absorption closely matches the AM1.5 solar spectrum, resulting in an excellent solar absorption efficiency of 97 % in the 280–5000 nm range. The structure retains high absorption from normal incidence up to 60° and exhibits a thermal emission efficiency of 96.96 % at 2000 K, along with a photothermal conversion efficiency exceeding 91.5 % over the temperature range of 300–1000 K at a solar concentration factor of 1000. These enhancements demonstrate that the proposed metastructure is a highly promising candidate for advanced solar-thermal applications, including solar water heating, photothermal therapy, and concentrated solar power systems.
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